Ligamentum Flavum Buckling vs Hypertrophy in Cervical Myelopathy Using Dynamic Imaging: Are Instability and Loss of Disc Height the Culprits?

BACKGROUND

The literature has not distinguished between LF "hypertrophy" and "buckling" when addressing cervical spondylotic myelopathy. The identification of buckling on dynamic magnetic resonance imaging can determine the levels for decompression more accurately and modify the surgical plan accordingly. No studies have been performed in the cervical spine to analyze the factors affecting LF buckling.

PURPOSE

Our objective was to investigate the factors affecting static ligamentum flavum (LF) "hypertrophy" and dynamic LF "buckling."

STUDY DESIGN

Retrospective cohort study.

METHODS

We conducted a retrospective study of hospital records and imaging database from January 2014 to January 2020. The relation of age, disc height, and intervertebral instability to LF hypertrophy and buckling were assessed.

RESULTS

Measurements were performed from C2-3 to C7-T1 in 169 patients who satisfied the eligibility criteria, making a total of 1014 levels. The samples were divided into 2 groups: 798 levels with buckling <1 mm (group A) and 216 levels with buckling >1 mm (group B). Of those, 161 levels satisfied the criteria for radiological instability (sagittal translation/rotation). No correlation was observed between age/disc height and buckling. Intervertebral instability showed significant association ( = 0.046) with buckling. No correlation was found between age/intervertebral instability and hypertrophy.

CONCLUSION

LF buckling but not hypertrophy is related to intervertebral instability in the cervical spine. LF buckling in the cervical spine is not related to age or disc height in the cervical spine.

CLINICAL RELEVANCE

Intervertebral instability on dynamic x-ray imaging of the cervical spine can be a predictor of ligamentum flavum buckling and can be utilized for surgical planning.